Tunisian special forces fought a gun battle with the ousted president's security force near the presidential palace on Sunday, a military source said, two days after Zine al-Abidine Ben Ali was ousted after more than 23 years as president.
Ben Ali fled to Saudi Arabia following a month of protests over poverty, jobs and repression that claimed scores of lives.
Parliament speaker Fouad Mebazza, sworn in as interim president, has asked Prime Minister Mohamed Ghannouchi to form a government of national unity and constitutional authorities said a presidential election should be held within 60 days.
While there have been relatively positive noises from the talks so far, the negotiations may run into trouble when they get down to the detail of which parties get which cabinet posts and how many of the old guard are included.
Ahmed Ibrahim, head of the opposition Ettajdid party, said the main thing now was to stop disorder.
"We are in agreement on several principles concerning the new government. We will continue to discuss. My message is to say 'no' to Gaddafi: we do not want to go backwards," he said, in reference to a speech by Libyan leader Muammar Gaddafi who said Tunisians were too hasty to get rid of Ben Ali.
Opposition parties want assurances that presidential elections will be free, that they will have enough time to campaign, that the country will move towards greater democracy and that the power of the ruling RCD party will be loosened.
Two opposition parties have also already said the two-month deadline for holding elections is too soon.
Opposition leader Najib Chebbi said after talks with Ghannouchi on Saturday that elections could be held under international supervision within six or seven months.
Beirut-based commentator Rami Khouri said it could take a while for Tunisia's opposition of secularists, leftists and Islamists to coalesce because there was no unified movement.
"The process will probably take weeks at least and then you have to sort out the logistics of the interim government, the unity cabinet [...] you have never had an Arab country where the people can suddenly start from scratch," he told Reuters.
Arab rulers worry
Tunisia's political earthquake has shattered the cosy world of entrenched Arab rulers and destroyed the image of their military-backed regimes as immune to popular discontent and grievances.
Analysts, opposition figures and ordinary people say the Tunisian revolt may prove contagious. Like Tunisians, many Arabs are frustrated by soaring prices, poverty, high unemployment, a bulging population and systems of rule that ignore their voices.
These leaders, they say, can no longer just ignore the plight of their poor or rely on subduing their restive populations with brute force without retribution.
"The developments in Tunisia are like an earthquake. Arab rulers will try to loosen up their regimes by giving some freedom, providing jobs and education and other things. Then they will try to become repressive again," said Mohammed al-Qahtani, a Saudi opposition activist based in Riyadh.
"The question will be if people have learned their lessons and will let them get away it."
Ordinary Arabs may be less willing now to accept their governments' old political tactics. Stunned by TV footage from Tunis, many are wondering if the same could happen at home. "Tyrants don't last forever. This is a clear message to every dictatorial regime that rules by iron and fire," said a commentator on a discussion forum, UAE Hewar.
"The Tunisians are real men. They took matters into their own hands and had the courage to control their own fate and said 'no' to oppression," said a 55-year-old Egyptian veteran of the 1973 war with Israel, who asked not to be named.
"The Egyptian people suffer just like the Tunisians, and this encourages all Egyptians to do the same."
Social networks: new weapon
Social networking sites in the region have lit up with calls for action. Twitter and Facebook have changed the rules for Arab governments who could once spoon feed news to their people.
"People cannot be bought forever with economic goodies in an age of information flowing freely. Today, people can make comparisons," said Jasim Husain, an opposition member of Bahrain's parliament.
In Egypt, where President Hosni Mubarak has been in power for three decades, one Facebook page was entitled "Project to prepare a plane for each president" and several pages called on the 82-year-old leader to start packing his bags.
"Enough is enough. We are fed up and we will not let our country slip from our hands any longer," said one Facebook user. Another called on Tunisia's exiled president, Zine El Abidine Ben Ali, to "tell Mubarak a plane is also waiting for him".
"Make it one plane to fly around and pick them all up," said Facebook user Maha al-Gamal.
North African states stretching from Morocco to Egypt, plus Jordan and Syria, are among the countries seen most susceptible to upheaval by restive populations. Arab states in the oil-producing Gulf have more resources to buy off citizens.
"I think the Gulf states are a little bit more secure than some of the other states that have been mentioned, such as Egypt and Jordan and Algeria. So I don't see it spreading to here," said Theodore Karasik, analyst at Dubai-based group INEGMA.
(EurActiv with Reuters.)